The present invention relates to an electric toothbrush and this invention provides a new electric toothbrush which can remove dental, bacterial plaque and keep the oral cavity and teeth clean and healthy to prevent decayed tooth and pyrrhoea, or Rigg's disease, and other diseases of tooth and teethridge or gums.
An electric toothbrush which moves a brush member or fillings i.e., bristles or filaments, back and forth at a high speed in a vertical (up-and-down) or lateral (side-to-side) direction relative to a denture, i.e., an arrangement of teeth, in an arc shape is known and available in the market. In the conventional electric toothbrush, the brush is moved along, and in parallel with, a surface of the tooth, in the same manner as manual toothbrushing.
However, in the conventional manual and automatic toothbrushing operation, in which the brush is moved along, and in parallel with, a surface of the tooth, the brush fillings (i.e., natural or man-made hairs or filaments) are bent and, therefore, only a small force by a bending stress is delivered to a tip of each of the fillings of the brush. Accordingly, it is quite difficult to remove dental, bacterial plaque. Further, since the denture is formed with continuous, irregular undulations of tooth surface, a high speed or high stroke brushing fails to capture the important spots and places such as the portion between adjacent teeth, teethridge, and it is likely that the fillings of the brush jump over these important places to be cleaned where the bacterial plaque adheres. Further, the conventional electric toothbrush has the disadvantage that if it is operated at high speed, it is difficult to handle the toothbrush so that tips of the brush filling are focused on the brushing point. In addition, the conventional electric toothbrush has brush fillings which are stiff and have a stiffness as hard as that of manually operated toothbrushes. Thus, a rapid and/or large-length movement of the toothbrush causes excoriation of the teethridge and dental abrasion or abrasion of dental tissue.
In general, dental plaque is not so hard, but rather soft, viscous and paste-like. In order to strip off such a dental plaque from the surface of teeth, the applicant has found that it is necessary to push the toothbrush softly in a vertical manner against the tooth surface with the fillings of the toothbrush being erected vertical to the tooth surface so that the fillings can be slightly curved and then moved along the tooth surface by a self-recovery force of the curved fillings of the brush. Thus, the fillings will not jump over the portion to be brushed, but catches the spot of dental plaque. In the present invention, each filling of the brush, which is made, for example, of nylon, is utilized as a `column` which receives a compression force which induces a bending stress as known in the technological field of material mechanics, and an alternating stress (i.e., alternating compression and tension) is added repeatedly and rapidly to the fillings (`columns`) so that stronger force is delivered to tips of the fillings even though each filling has a thickness smaller than the conventional ones. The tips of the brush fillings are rapidly and finely moved to efficiently remove the dental plaque without damage in teethridge.